Tips on Hard Drive Care?

I've really never heard of a hard drive being sideways causing any sort of damage. I've been running a spare harddrive in my CPU for about 2-3 years now with no problems, and it is suspended sideways. Also, my harddrive enclosure kit is positioned sideways, and it is a 400gig that I've had for about 2 years now and I've had no problems. But I have heard about what mortis mentioned; reducing the turning on and turning off of the harddrive. Booting a harddrive is much harder on it than it continuously running from what I've heard. You can also get programs that check the health of your harddrive, which is always a good thing so that you can check up on it, and see if there's any areas you need to do better in (such as temp).

Jam it back in, in the dark.